In today’s AI-driven world, it’s tough to tell whether a particular YouTube video is real or AI fakery. But back in 2010, before AI was an everyday thing, Mercedes-Benz made a commercial featuring an SLS AMG driving upside down in a tunnel. The commercial was striking at the time, but it turns out that part of that imagery was digitally created. However, 16 years later, Chinese automaker Voyah attempted the same stunt without any digital or AI help. And various calculations suggest that its tunnel-bound heroics were perfectly feasible.
Mercedes-Benz Made An Impossible-Looking Commercial, Not An Impossible Stunt
Rear shot of a 2011 Mercedes-Benz SLS AMG with its gullwing doors openMercedes-Benz
Mercedes certainly wanted to make an impact with its new SLS AMG in 2010. After all, this was the spiritual successor to the legendary 300SL Gullwing, and it had a 563-horsepower naturally aspirated V8, rear-wheel drive, and some extraordinary roof-hinged doors. Mercedes also had the services of F1 legend Michael Schumacher to help make an impact, and its goal was to suggest that Schumacher was behind the wheel, sending the car through a tunnel while performing a 360-degree loop.
Everything looked polished and spectacular in the subsequently aired ad, but a January 2010 report from the German newspaper BZ reported that the looping images were the result of digital effects. Mercedes had apparently envisioned something that could defy physics, given the right tunnel ramps, speed, and trajectory, but had still decided to use digital production to perfect the final visual product.
In 2026, Chinese manufacturer Voyah decided that it would prove the point conclusively without the aid of digital effects or AI specifically. It set up a test in which it would send its new Passion S into a closed tunnel near Wuhan at a speed of roughly 130 km/h, or 81 mph. A special transition zone would allow the car to climb from the roadway onto the inside surface of the tunnel before looping over and descending again on the opposite side. The car was basically a production-spec vehicle with full battery and driver assistance hardware in place.
The crucial part of the equation here appears to be the specially constructed ramps. Their presence meant that the driver didn’t have to try and steer up an ordinary vertical wall. If the vehicle hit the ramp carefully, that would place it on a naturally curved path, which means that it ought to reconnect safely with the road when it came down the other side.
But was Voyah’s speed actually fast enough to keep the car on the ceiling — or was this just a very expensive crash waiting to happen?
A Physicist Worked Out The Trick 16 Years Before Voyah Tried It
2026 Voyah Passion S rear quarterVoyah
In 2010, a renowned physicist determined that it was indeed possible for a car to perform such a stunt from a purely technical point of view. Rhett Allain published his findings on his Dot Physics blog at ScienceBlogs. He pointed out that the car would never be performing an ordinary vertical loop, but instead, would be traveling along the length of the tunnel while simultaneously rotating around its inner circumference. Its path would therefore be a spiral, or more accurately, a helix, and that changes the interpretation of the vehicle’s speed.
In this situation, if the vehicle’s speedo reads 81 mph, not all of that 81 mph is actually carrying the car around the circumference of the tunnel, as most of it is still propelling the vehicle forward. Only the circumferential component of the velocity is responsible for the radial acceleration that keeps the car following the curved surface of the tunnel. The velocity in the circular motion equation is not whatever appears on the speedometer, and the minimum circumferential/tangential speed required for a car to remain in contact with the ceiling was indeed only around 14.5 mph.
The scientist also estimated that the tunnel Mercedes used was about 8.5 m in diameter and went on to calculate a theoretical minimum circumferential speed of roughly 6.5 m/s, equating to 14.5 mph. He also estimated about 30 m/s of circumferential velocity from the apparent rotation shown in the commercial.
However, Allain did make a miscalculation in his original work when attempting to calculate the overall speed of the SLS. He used apparent 25 m tunnel markers, and this gave him the result of an absurd 117 m/s, translating to about 260 mph. He did update the post later when someone found that the markers were not reliably spaced. However, the most important discovery underlines that a car doesn’t have to rely on anything close to its entire road speed to keep it against the tunnel at the top. It only needs enough circumferential speed.
That’s the theoretical floor. Whether Voyah’s Passion S actually cleared it is a different calculation entirely.
The Passion S Numbers Work Better Than Expected
2026 Voyah Passion S cutaway floorpan and powertrainVoyah
In its media materials, Voyah suggests that the Passion S approached the crucial maneuver at around 130 km/h with a steering angle of about 16 degrees as the car entered the ramp and curved tunnel surface. And this led to some interesting findings given the dimensions of the car. Using the 1,998 mm width of the Passion S as a scale to estimate the dimensions of the tunnelsuggests that the radius of the car’s center-of-mass path is around 4.4 meters.
Using that 4.4 m radius figure, one complete revolution around the tunnel covers 27.65 m using a 2π × 4.4 calculation. And if the rotation visible in the footage takes about 3.0 seconds, then the Passion S should be moving around the tunnel’s circumference at about 9.2 m/s (33.2 km/h). If it takes 2.5 seconds instead, that rises to roughly 11.2 m/s (39.8 km/h).
When a car hits that crucial ceiling in such a test, it just needs enough inward acceleration that gravity can help to bend its path around the tunnel instead of allowing it to simply fall to the floor. At the absolute threshold where the tunnel itself exerts no additional normal force on the tires, the equation to use is v = √(gR). Once again, referring to the 4.4 m radius, the result is approximately 6.57 m/s or 23.7 km/h. And the low end of the video-derived 33 to 40 km/h circumferential range is comfortably above the theoretical minimum.
This means that the event footage provided by Voyah is perfectly feasible, and nothing visible would require fake physics. The observed rotation time, claimed road speed, estimated turn radius, and resulting helical path all point towards something believable.
2026 Voyah Passion S front quarterVoyah
When people see something that, on the face of it, appears to be too good to be true, they immediately tend to complain about AI or CGI. Voyah initially received a lot of that kind of blowback because its polished commercial looked almost too clean. However, it also decided to release an uncut one-take recording of the successful run during the launch of its Passion S. There also appears to be a separate video in which a camouflaged prototype loses contact with the tunnel and crashes back onto the road.
In the camo-footage, the Passion S appears to briefly lose contact while inverted before its wheels strike the road surface hard. The lower corner of the front bumper also seems to take a conspicuous hit when the vehicle returns to the road. Clearly, the glossy promotional video shows an always-pristine vehicle, but in any case, the messiness of the uncut version probably strengthens Voyah’s case.
It’s important to assess any back-of-the-envelope calculations through the harsh lens of reality. After all, the tunnel and ramp radius may change throughout the maneuver, and the vehicle speed may not be perfectly constant. The center of the vehicle’s mass will not always follow a geometrically perfect helix, and suspension movement could come into the picture where one surface transitions into another. But the bottom line is that math doesn’t rule the stunt out, even as Voyah doesn’t necessarily need perfect mathematics to make its case.
Being A Hefty EV Makes This Harder
2026 Voyah Passion S interior from the rearVoyah
It’s interesting to compare the weight of the two cars in these two experiments. In 2010, the SLS AMG weighed about 3,571 lbs, but in 2026, the Passion S Ultra+ usually weighs 5,688 lbs. That’s a huge difference between the two vehicles, but the extra mass doesn’t increase the theoretical minimum speed that the car needs to stay on the ceiling. After all, when mass enters the circular motion equation, it appears on both sides so it cancels itself out.
However, the fact that the Passion S is demonstrably heavy still matters enormously. Its greater mass produces larger absolute loads on the tires, wheels, suspension, wheel bearings, body structure, and especially the transitions into and out of the tunnel surface. And that may partly explain the ugly landing on the raw footage.
There’s still something legitimately impressive about a roughly 5,700 lb electric crossover completing this kind of maneuver. And that’s what probably makes Voyah’s attempt even more impressive than that of Mercedes-Benz. After all, in 2010, Mercedes-Benz was dealing with one of the great modern supercars and also had one of the greatest Formula 1 drivers of all time on hand, in an advisory role if nothing else.
Sixteen years after Mercedes’ controversial event, Voyah showed up with a huge battery-laden electric crossover that weighed well over two tons, in a comparison that’s almost comical. And while AMG may have ultimately faked the final pictures back in 2010, Voyah appears to have actually pulled off the stunt today. And this time, with math to back it up.
Sources: Mercedes-Benz, Voyah, ScienceBlogs, BZ newspaper.
